To appropriately move a tape cassette, tape withdrawal posts, and a capstan pinch roller in connection with multiple modes (a cassette eject mode, a cassette lowering mode, a replay mode, a reverse replay mode, and a rapid traverse and rewind mode), conventional video tape recorders drive these components via a link mechanism that engages with a main cam gear while rotating the main cam gear using a single DC motor.
FIG. 3 shows a structure for controlling the operation of the motor for driving the main cam gear. A DC motor 1 is coupled to a main cam gear 3 via a speed reducing mechanism 2. The main cam gear 3 is rotated to drive via a main lever 4 (see FIG. 4) that extends along a cam groove (not shown) for the main cam gear 3 and a link mechanism 5 composed of various levers and gears coupled to the main lever 4, a tape cassette elevating drive section 6, a tape loading drive section 7, a pinch roller drive section 8, and a clutch and brake drive section 9 so that they will perform an intended operation during an appropriate period of time.
A rotary encoder 10 for detecting the rotational position of the main cam gear 3 in terms of an absolute value is coupled to the main cam gear 3, and based on an instruction input from an operation panel 12 and data detected by the rotary encoder 10, a microcomputer 11 controls the turning-on and -off of the power to the motor, the polarity of the power, and the turning-on period so that the main cam gear 3 will be rotated and stopped at a rotational position corresponding to the instruction input from the operation panel 12.
As shown in FIGS. 4 and 5, the tape loading drive section 7 that withdraws a magnetic tape from a tape cassette and winds it over a rotating head cylinder 13 including a pair of tape withdrawal posts 7a and 7b.
The tape withdrawal posts 7a and 7b engage with guide grooves 15a and 15b formed in a chassis 14 for slidable movement and are coupled to the tips of loading arms 16a and 16b shown in FIG. 5, with the proximal ends of the loading arms 16a and 16b coupled via pins 19a and 19b to levers 18a and 18b that are rotated integrally with gears 17a and 17b meshing with each other. One of the gears 17a and 17b meshes with a rack 20 (see FIG. 4) engaging with the main lever 4 so that the tape withdrawal posts 7a and 7b can be transferred between the position shown by the imaginary line in FIG. 5 and the loading completion position shown by the solid line.
A cleaner head 22 with its middle pivoted on a shaft 21 buried in the chassis 14 is installed near the rotating head cylinder 13. While the tape withdrawal posts 7a and 7b are moving from the position shown by the imaginary line to the loading completion position, a felt portion 22a at the tip of the cleaner head 22 temporarily contacts the head of the rotating head cylinder 13 for cleaning, as shown in FIGS. 4, 6, and 7.
Specifically, when a boat 23 with the tape withdrawal post 7b mounted thereon contacts at a point P an elastic portion 22b formed at the proximal end of the cleaner head 22 and moves toward the loading completion position, as shown in FIG. 4, the felt portion 22a of the cleaner head 22 contacts the rotating head cylinder 13, which is rotating, under a pressing force generated by the elastic deformation of the elastic portion 22b, as shown in FIG. 6. Then, when the tape withdrawal post 7b has reached the loading completion position, as shown in FIG. 7, the felt portion 22a of the cleaner head 22 leaves the rotating head cylinder 13.
FIG. 8 shows a flowchart of the microcomputer 11 describing the operation performed when the microcomputer 11 detects the insertion of a tape cassette.
On detecting the insertion of a tape cassette at step #1, the microcomputer 11 rotates the DC motor 1 forward at step #2, and checks whether data detected by the rotary encoder 10 has reached a play position (tape loading has been finished and a magnetic tape is sandwiched between the capstan and the pinch roller).
The microcomputer repeats steps #2 and #3 until the main cam gear 3 has reached the play position, and on detecting the arrival at the play position at step #3, the microcomputer 11 turns off the power to the DC motor 1 at step #4.
At step #5, the microcomputer detects whether or not a play button in the operation panel 12 has been pressed, and if so, it rotates the capstan to start the running of the tape at step #6. Otherwise, the microcomputer executes step #7 to check whether or not a specified period of time T1 has passed since the start of step #5. If not, the microcomputer checks at #8 whether or not timer reservation has been reserved. Otherwise, the microcomputer returns to step #6.
If the operator has inserted and left the tape cassette as it is without operating the operation panel 12, the microcomputer detects the passage of the specified period of time T1 at step #7 and turns off the power at step #9 to transfer to a standby state. If the microcomputer detects a timer operation at step #8 before detecting the passage of the specified period of time T1 at #7, it reserves the timer, turns off the power, and transfers to the standby state at step #10.
In such a conventional configuration, when the tape cassette is inserted, the cleaner head 22 contacts and automatically cleans the rotating head cylinder 13 in steps #1 to #4. Automatic cleaning is also provided when an eject command is issued from the operation panel 12.
Despite such cleaning of the head of the rotating head cylinder 13 using the cleaner head 22, degraded recording and reproduction may be caused by the contamination of the head of the rotating head cylinder 13.